Storage battery control device, power storage system, and storage battery control method

Abstract

A storage battery control device controls a power storage system including a plurality of storage battery strings connected in parallel to each other, each of the storage battery strings including a plurality of storage batteries connected in series and a power converter configured to convert an input/output power of the storage battery string. An instruction value of power or current of charge or discharge of the storage batteries string is set, and when the instruction value changes from a current value to a target value, a process of changing the instruction value to the target value by a small amount of change that is less than a difference between the target value and the current value is repeatedly executed until the instruction value reaches the target value.

What is claimed is: 
     
         1 . A storage battery control device that controls a power storage system including a plurality of storage battery strings connected in parallel to each other, each of the storage battery strings including a plurality of storage batteries connected in series and a power converter configured to convert an input/output power of the storage battery string, wherein:
 an instruction value of power or current of charge or discharge of the storage batteries string is set; and   when the instruction value changes from a current value to a target value, a process of changing the instruction value to the target value by a small amount of change that is less than a difference between the target value and the current value is repeatedly executed until the instruction value reaches the target value.   
     
     
         2 . The storage battery control device according to  claim 1 , wherein
 the target value is set to be lower than a limit value of power or current of charge or discharge of the storage battery string.   
     
     
         3 . The storage battery control device according to  claim 2 , wherein
 whether the current value is the limit value or higher is determined, and when it is determined that the current value is the limit value or higher, the instruction value is changed to a value lower than the limit value.   
     
     
         4 . The storage battery control device according to  claim 1 , wherein:
 a predetermined priority is set depending on a state of the storage battery string; and   as the predetermined priority of the storage battery string becomes higher, the target value is set to be higher.   
     
     
         5 . The storage battery control device according to  claim 4 , wherein
 the predetermined priority is set to be higher as a cumulative charge/discharge capacity of the storage battery string decreases or is set to be higher as a SOH of the storage battery string increases.   
     
     
         6 . The storage battery control device according to  claim 4 , wherein
 the predetermined priority is randomly set whenever the instruction value changes from the current value to the target value.   
     
     
         7 . The storage battery control device according to  claim 1 , wherein:
 the instruction value is set for the plurality of storage battery strings; and   when the instruction value changes from the current value to the target value simultaneously in the plurality of storage battery strings, a process of changing the instruction value to the target value by a small amount of change that is less than a difference between the target value and the current value is repeatedly executed until the instruction value reaches the target value.   
     
     
         8 . A power storage system comprising:
 a plurality of storage battery strings connected in parallel to each other; and   a storage battery control device configured to control the storage battery strings, wherein   each of the storage battery strings includes: a plurality of storage batteries connected in series; and a power converter configured to convert an input/output power of the storage battery string; and   in the storage battery control device, an instruction value of power or current of charge or discharge of the storage battery string is set, and when the instruction value changes from a current value to a target value, a process of changing the instruction value to the target value by a small amount of change that is less than a difference between the target value and the current value is repeatedly executed until the instruction value reaches the target value.   
     
     
         9 . A storage battery control method that is executed by a storage battery control device for controlling a power storage system including a plurality of storage battery strings connected in parallel to each other, each of the storage battery strings including a plurality of storage batteries connected in series and a power converter configured to convert an input/output power of the storage battery string, the storage battery control method comprising:
 setting an instruction value of power or current of charge or discharge of the storage battery string; and   repeatedly executing a procedure of changing the instruction value to a target value by a small amount of change that is less than a difference between the target value and the current value until the instruction value reaches the target value when the instruction value changes from a current value to the target value.